[Tuxpaint-devel] Text/Label "paste" functionality

[Bill K. <nb...@so...>]

I've begun implementing a text clipboard 'paste' function in the Text & Label tools,
via [Ctrl]+[V] on a physical keyboard [1], and a new "Paste" button in the on-screen
keyboard (OSK) built into Tux Paint [2].

Right now, it wraps at a character level, if you paste text that will go beyond
the right edge of the canvas.  If the text continues to the bottom of the canvas,
it will abort (thus truncating the text).  I'm thinking of adding better word
wrapping (via spaces & perhaps punctuation) if I can manage it -- probably
cribbing code used by the button labelling routine.

I also took the opporunity to update the documentation about the OSK in both
the user-facing "README", and the more technically-inclined "EXTENDING".

I'd appreciate people poking & prodding at it, and reporting back any issues
or ideas for improvement.

Thanks very much!  And happy holidays & new year!

-bill!

[1] Mark, should we also support [Option]+[V] on macOS?
[2] Pere, does Android need something added to support such a function with its
    OS-level on-screen keyboard?